1. Field of the Invention
The present invention relates in general to magnetic recording systems, and more particularly to magnetic recording systems having write heads with improved flare definition and method of its manufacture.
2. Description of the Related Art
Fixed magnetic storage systems are now commonplace as a main non-volatile storage in modern personal computers, workstations, and portable computers. Storage systems are now capable of storing gigabyte quantities of digital data, even when implemented in portable computers.
As disk drive technology progresses, more data is compressed into smaller areas. Increasing data density is dependent upon read/write heads fabricated with smaller geometries capable of magnetizing or sensing the magnetization of correspondingly smaller areas on the magnetic disk. The advances in magnetic head technology has led to heads fabricated using processes similar to those used in the manufacture of semiconductor devices.
A typical disk drive is comprised of a magnetic recording medium in the form of a disk for storing information, and a magnetic read/write head for reading or writing information on the disk. The disk rotates on a spindle controlled by a drive motor and the magnetic read/write head is attached to a slider supported above the disk by an actuator arm. When the disk rotates at high speed a cushion of moving air is formed lifting the air bearing surface (ABS) of the magnetic read/write head above the surface of the disk.
The read portion of the head is typically formed using a magnetoresistive (MR) element including giant magnetoresistive heads in current in- and perpendicular- to plane configurations, and sensor using tunneling current. This element is a layered structure with one or more layers of material exhibiting the magnetoresistive effect. The resistance of a magnetoresistive element changes when the element is in the presence of a magnetic field. Data bits are stored on the disk as small, magnetized region on the disk. As the disk passes by beneath the surface of the magnetoresistive material in the read head, the resistance of the material changes and this change is sensed by the disk drive control circuitry.
The write portion of a read/write head is typically fabricated using a coil embedded in an insulator between a top and bottom magnetic layer. The magnetic layers are arranged as a magnetic circuit, with pole tips forming a magnetic gap at the air bearing surface of the head. When a data bit is to be written to the disk, the disk drive circuitry sends current through the coil creating a magnetic flux. The magnetic layers provide a path for the flux and a magnetic field generated at the pole tips magnetizes a small portion of the magnetic disk, thereby storing a data bit on the disk.
The process for fabricating the write portion of a read/write head typically uses processes that define the width of pole tips. Furthermore, write head flare, which is the area where the second pole piece begins to widen above the air bearing surface, is not well defined due to limited capability of alignment in optical lithography. Because flare point placement directly affects the magnitude of the write field at the recording medium, inaccurate placement of the flare point can result in non-functioning head. This situation is especially serious for perpendicular recording, since the required accuracy of the flare position exceeds the processing tolerances, resulting in enormous yield loss in head fabrication.
It can be seen therefore, that there is a need for a method of defining write head flare with high degree of accuracy.